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Assessment of heavy metal content in some selected agricultural products planted along some roads in Nassarawa State, Nigeria
(2006) Aremu, M.O., Olonisakin,A., Ahmed, S.A
Effect of solvents on the electronic absorption spectra of 9,14 dibenzo (a, c) phenazine and tribenzo (a, c, i) phenazine
(2009) M. D. Adeoye, A. I. Adeogun, S. Adewuyi, S. A. Ahmed, N. W. Odozi and N. O. Obi-Egbeedi
9,14-dibenzo (a, c) phenazine and tribenzo (a, c, i,) phenazine, were synthesized and solvent effect on the electronic absorption spectra of the compounds were studied. In some aspects of the spectra, the features of anthracene were carried into the spectrum of these synthesized phenazine derivatives with a change in symmetry. The absorption spectra of the two compounds were red–shifted compared with that of phenazine. Polar solvents shift the wavelength of absorption to the red relative to non-polar solvents, thus revealing that the observed bands have more charged excited state. This suggests that the transition is p p* transition.
Nuclear Magnetic Resonance and Infra Red Spectroscopic Studies of some Metal Complexes of Maleoyl-p-Aminobenzoic acid
(Faculties of Life and Physical Sciences, University of Ilorin, Nigeria, 2010) Bale, Adebayo Tajudeen; Eke, Uche Basil
Metal complexes of p-Aminobenzoic acid derivative of maleic anhydride were investigated. Thus, N-(4-carboxy-phenyl) maleimide and its sodium salt (sodium N-maleoylbenzoate) were prepared. The sodium salt was complexed with some transition metals (Co2+, Ni2+, Zn2+ and Cu2+). Complexes separated as precipitates from the reaction mixtures and were characterized by spectroscopic studies.
Effects of solvent on the UV-visible absorption spectra of acenaphtho(1,2-b) quinoxaline and acenaphtho(1,2- b)benzo(g)quinoxaline
(2011) S. A. Ahmed, N. O. Obi-Egbedi, N. W. Odozi, I. Iweibo and M. D. Adeoye
The effects of solvent on the electronic absorption spectra has been used to investigate the structural and molecular properties of acenaphtho(1,2-b)quinoxaline and acenaphtho(1,2-b) benzo(g)quinoxaline. The structures of the compounds have been established by UV-visible spectrophotometer. The spectra behaviours in terms of dipole moments in the ground and excited states have been interpreted and related to the transition energies, intensities and the molecular structures of the compounds.
Removal of arsenic from aqueous solution by synthetic hematite
(Journal of Chemical Society of Nigeria, 2011) Adekola, F. A.; Abdus-Salam, N.; Abdulrauf, L. B.
A sample of hematite has been prepared and characterized by determination of some physico-chemical parameters such as X- ray Diffraction analysis, specific gravity and point of zero charge measurement. The potential of synthesized hematite for the sorption of arsenic(III) aqueous solution was also investigated, and the sorption data were found to be fitted with Langmuir adsorption isotherm (type 2) as well as Freundlich and Temkin isotherms with corresponding correlation coefficient (R) of 0.96, 0.94 and 0.94 respectively. The adsorption capacity calculated from the Freundlich and Langmuir isotherms were 0.35 and 0.60 respectively. The sorption kinetics was also investigated and the equilibrium time determined to be 320mins. The kinetics was found to follow pseudo – first order kinetics. Desorption study was also carried out with concentrated HNO3 (1M), and was found to be effective for the stripping of 86% of pre – sorbed arsenic from the adsorbent after the first use
Removal of arsenic from aqueous solution by synthetic hematite
(Journal of Chemical Society of Nigeria, 2011) Adekola, F. A.; Abdus-Salam, N.; Abdulrauf, L. B.
An hematite was synthesized and subjected to batch equilibration ofarsenic and its desorption processess that control the mobility, toxicity and availability in the water environment
Synthesis and Characterization of Transition Metal Complexes of Cu(II), Ni(II), Co(II) and VO(IV) with Tetradentate Ligands Derived from Substituted Acetophenone and Benzophenone
(2011-06-30) Osunniran, W. A. and A. C. Tella.
Two tetradentate Schiff base ligands, N,N´-bis(2-hydroxy-5-methoxyacetophenone) ethylenediimine (MaenH2) and N,N´-bis(2-hydroxy-4-methoxybenzophenone) ethylenediimine(MbenH2) were formed by 1:2 molar condensation of ethylenediamine with 2-hydroxy-5-methoxyacetophenone and 2-hydroxy-4-methoxybenzophenone respectively. These Schiff base ligands formed complexes (1:1 molar ratio) with Copper, Nickel, Cobalt and Oxovanadium ions. The complexes were characterized by Infrared, Electronic Spectra and elemental analysis. The spectra data of the ligands and their complexes were discussed based on the structural changes which occur due to complexation. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.
Amphetamines analysis in wastewaters – method performance of solid phase extraction-higher performance liquid chromatography mass spectrometry techniques (SPE-HPLC MS/MS).
(Leibniz Research Centre for Working Environment and Human Factors., 2011-08-19) Mustapha, A.O. and Usman L.A
Recently, many articles have reported different levels and distribution of amphetamine hither-to detected in biological fluids now appreciably found in aquatic environment at ng/L levels. Identification and measurement of amphetamine and its metabolites in surface and sewage waters using higher performance liquid chromatographic methodologies in the literatures now on current trend have provided information that are of scientific interest and effectively re-placed immunological methods which only suggest the presence of these substances. Active research on both distribution and impacts of this important drug of abuse and related metabo-lites in the wastewaters are on-going.
Endocrine disrupting compounds exposure and testis development in mammals
(Leibniz Research Centre for Working Environment and Human Factors., 2011-10-10) Biola F. Egbowon and Mustapha, A.O
In the last few decades, there is substantial evidence that male reproductive function is deteriorating in humans and wildlife and this is associated with unintentional exposure to widely used synthetic chemicals. Subsequently, much has been done to show that certain chemicals in the environment adversely interfere with the developing fetal gonads of the laboratory animals. Some in vitro studies have demonstrated treatment-induced reproductive problems in offspring exposed to endocrine disrupting compounds (EDC) which are similar to those observed in wildlife and human population. Few EDC studies have demonstrated that there are certain periods of gestation when the developing fetus is highly sensitive and at risk of small endocrine changes. Similar observations have been made in the sewage sludge model, however, while animal studies have been insightful in providing valuable information about the range of effects that can be attributed to in utero exposure to EDCs, varying levels of maternal doses administered in different studies exaggerated extrapolation of these results to human. Thus the EDC concentration representative of fetal exposure levels is uncertain because of the complexities of its nature. So far, the level of fetal exposure can only be roughly estimated. There is substantial evidence from animal data to prove that EDCs can adversely affect reproductive development and function in male and more has accumulated on the mechanisms by which they exert their effects. This paper therefore, reviews previous
Kinetics and thermodynamic studies of adsorption of malachite green onto unmodified and EDTA-modified groundnut husk
(2012) Bamgbose Janet Titilayo, Bamigbade Akeem Adesina, Nkiko Mojisola Olubunmi, Ahmed Sikiru Akinyeye and Ikotun Adebomi Ayodeji
A batch experiment was applied to study the adsorption of malachite green from aqueous solution by unmodified and ethylene diamine tetraacetic acid (EDTA)-modified groundnut husk. The effect of initial dye concentration, temperature, contact time and pH on the sorption process was investigated. The Langmuir and Freundlich adsorption isotherms were applied to test the experimental data. The chemically modified groundnut husk agreed well with both the Langmuir and Freundlich models at the temperature below the room temperature (25°C) and above the room temperature. Unmodified groundnut husk showed poor agreement with the isotherm at temperature below the room temperature but fits well into the model at higher temperature. Kinetics of the adsorption with respect to the initial dye concentration and temperature was also investigated. The pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to test the kinetic data. Obtained data were fitted properly in the pseudo-second-order kinetic model. The thermodynamic parameters such as change in free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) were also determined and the results obtained confirmed that the sorption process is feasible, spontaneous, and endothermic.
Solvent Perturbation of the Electronic Intensity of Solvated Absorbing Molecules
(2012) Sikiru A. Ahmed, Nelson O. Obi-Egbedi, Idowu Iweibo
In this paper, we present a general expression originating from quantum-mechanical perturbation treatment of electronic intensities and Hamiltonian operators for the system (HA and HB) of an absorber and a perturber respectively. The expression is related to the Longuet-Higgins’ definition of solute-solvent interaction and fitted into linear regression mode for the determination of transition polarizabilities of 9H-xanthene, 9H-xathone and 9H-xanthione. The result conforms to those earlier obtained when all possible interaction modes are considered.
Biosorption of Cr (VI) ion from Aqueous Solution by Maize Husk: Isothermal, Kinetics and Thermodynamic Study
(2012) ADEOGUN ABIDEEN IDOWU, OFUDJE ANDREW EDWIN, IDOWU MOPELOLA ABIDEMI, AHMED SIKIRU AKINYEYE AND SARAFADEEN OLATEJU KAREEM
The kinetics, equilibrium and thermodynamic of the biosorption of Cr (VI) ion onto maize husk biomass from aqueous solution were investigated. The effects of contact time, initial metal concentration, pH, temperature as well as modification with oxalic acid on biosorption capacity were studied. The maximum biosorption capacity of the untreated corn shaft biomass (UTCS) was found to be 28.49 mg g-1 which slightly increased to 29.33 mg g-1 when treated with oxalic acid treated corn shaft biomass (ATCS). The kinetics studies showed that the biosorption process of the metal ion fitted well with second order model. The calculated thermodynamic parameters (∆Go, ∆Ho and ∆S◦) showed that the biosorption of Cr (VI) ion onto the biomass maize husk is feasible, spontaneous and exothermic in nature.
Kinetic, thermodynamic and isothermal parameters of biosorption of Cr (VI) and Pb (II) ions from aqueous solution by biosorbent prepared from corncob biomass
(2012) Adeogun A.Idowu, Andrew E.Ofudje, Idowu M.Abidemi, Ahmed S.Akinyeye
The kinetics, equilibrium and thermodynamic of the biosorption of Cr (VI) and Pb (II) ions onto corncob from aqueous solution were investigated. Optimum experimental parameters were determined to be pH 5.8 for Pb (II) and pH 2.0 for Cr (VI), contact time of 80 min, and temperature 25 C. The maximum biosorption capacity of the biomass was found to be 8.07 mg g-1 for Cr (VI) and 9.05 mg g-1 for Pb (II). Upon treatment with oxalic acid, the values of maximum biosorption capacity for Cr (VI) and Pb (II) were found to be 10.74 and 10.27 mg g-1 respectively. The kinetic studies showed that the biosorption process of the metal ions fitted well with second order model. The calculated thermodynamic parameters (G, H and S) showed that the biosorption of Cr (VI) and Pb (II) ions onto corncob biomass is feasible, spontaneous and exothermic in nature.
Recent developments and applications of microextraction techniques for the analysis of pesticide residues in fruits and vegetables. In: Pesticides – Recent trends in pesticide residue assay
(Intech Open, 2012) Tan, G. H.; Abdulrauf, L. B.
Analysis of pesticide residues and other contaminants in fruit and vegetable samples is becoming increasingly important due to the health hazards caused by their accumulation in human tissue. The body requires some important nutrients which can be provided by the consumption of fruits and vegetables. The purpose of any analytical study is to obtain information about substances and analytes present in the sample. Analytical process involves several steps: sampling, sample preparation, separation, quantification and data analysis
APPLICATION OF FACTORIAL DESIGN TO THE STUDY OF PARAMETERS IN THE DETERMINATION OF PESTICIDE RESIDUES IN APPLE BY HEADSPACE SOLID PHASE MICROEXTRACTION COUPLED TO GAS CHROMATOGRAPHY-MASS SPECTROMETRY
(PACCON International Conference, 2012) Abdulrauf, L. B.; Tan, G. GH.
Solid-phase microextraction (SPME) is a solvent-less sample preparation method which combines sample preparation, isolation, concentration and enrichment into one step. SPME process involves two basic steps which are the partitioning of analytes between the polymeric fiber coating and the sample matrix, and desorption of the concentrated extracts into the analytical instrument, without any clean-up step. In this study, factors affecting the solid phase microextraction of pesticide residues (fenobucarb, diazinon, chlorothalonil and chlorpyrifos) were studied using a factorial design. The interactions and effects of temperature, time and salt addition on the efficiency of the extraction of the pesticides were evaluated using 23 factorial designs. A 10 g sample was weighed into 20 mL amber glass vial, fortified with the standard mixture at three concentration levels (10, 50 and 100 µg.L–1) and allowed to rest for 2 hrs. Optimum dilution was made with 10 mL of distilled water containing 10% NaCl and the mixture was shaken ultrasonically for 3 min. The analytes were then extracted with 100 µm PDMS fibers according to the factorial design matrix and desorbed into gas chromatography–mass spectrometry detector. The developed method was applied for the analysis of apple samples and the limit of detections was between 0.01 and 0.2 µg.L–1, which were lower than the MRLs for apples. The relative standard deviations were between 0.1 and 13.37% with average recovery of 80 to 105%. The linearity ranges from 0.5 – 50 µg.L–1 with RSD greater than 0.99
The Impact of Diesel Contaminated Soil on Seedling Growth of Okro (Abelmoschus Esculentus), Pumpkin (Amaranthus Hybridus) Maize (Zea Mays) and Pepper (Capsicum Annum)
(2012) Oludele Olusanya Emmanuel; Ogundele Damilola Tope
Coordination Compounds of n-phthaloylglycine and n-phthaloyltyrosine and their antimicrobial activities.
(2012-03-28) Adedibu, C. Tella, Stephen O. Oguntoye, Osunniran, W. A. and Rotimi O. Arise
Coordination compounds derived from N-phthaloylglycine and N-phthaloyltyrosine were synthesized. The ligands were formed by 1:2 molar condensation of phthalic anhydride with tyrosine and glycine respectively. The complexes were formulated as [Zn(PHG)2 (H2O)2] (OAc)2[1], [Ni(PHG)2 (H2O)2] (OAc)2 [2] and [Cu(PHT)2 ] (OAc)2 [3] characterized by melting point, conductivity, AAS , IR, Uv-Visible spectroscopies. Both ligands were found to be bidentate. For complexes [1] and [2] the metal ions coordinate through both oxygen of OH and C=O in the carboxylic group to give octahedral geometry whereas in the [3] the coordination of metal ion occurs through both oxygen of phenoxyl and carbonyl group resulting in tetrahedral geometry. The antimicrobial studies using four test organisms(P.aerugenosa, E.Coli, S. aureus and C. albicans) revealed that the metal complexes exhibit higher activity than their respective ligands.
Recent developments and applications of liquid phase microextraction in fruits and vegetables analysis
(Journal of Separation, WILEY-VCH, 2012-08-27) Abdulra’uf, L. B., Sirhan, A. Y. and Tan, G. H.
The sample preparation step has been identified as the bottleneck of analytical methodology in chemical analysis. Therefore, there is need for the development of cost-effective, easy to operate, and environmentally friendly miniaturized sample preparation technique. The microextraction techniques combine extraction, isolation, concentration, and introduction of analytes into analytical instrument, to a single and uninterrupted step, and improve sample throughput. The use of liquid-phase microextraction techniques for the analysis of pesticide residues in fruits and vegetables are discussed with the focus on the methodologies employed by different researchers and their analytical performances. Analytes are extracted using water-immiscible solvents and are desorbed into gas chromatography, liquid chromatography, or capillary electrophoresis for identification and quantitation.
Applications of solid phase microextraction for the analysis of pesticide residues in fruits and vegetables: A review.
(Journal AOAC International, Association of Official Analytical Chemists International (AOAC), 2012-09-01) Abdulra’uf, L. B., Chai, M. K. and Tan, G. H.
This paper reviews the application of various modes of solid-phase microextraction (SPME) for the analysis of pesticide residues in fruits and vegetables. SPME is a simple extraction technique that eliminates the use of solvent, and it is applied for the analysis of both volatile and nonvolatile pesticides. SPME has been successfully coupled to both GC and LC. The coupling with GC has been straightforward and requires little modification of existing equipment, but interfacing with LC has proved challenging. The external standard calibration technique is widely used for quantification, while standard addition and internal or surrogate standards are mainly used to account for matrix effects. All parameters that affect the extraction of pesticide residues from fruits and vegetables, and therefore need to be optimized, are also reviewed. Details of the characteristics of analytical procedures and new trends in fiber production using sol-gel technology and molecularly imprinted polymers are discussed
Heavy Metals Levels in Forage Grasses, Leachate and Lactating Cows Reared around Lead Slag Dumpsites in Nigeria
(Int. J. Environ. Res., 2012-09-12) Ogundiran, M. B.*, Ogundele, D. T., Afolayan, P. G.and Osibanjo, O.
A field study was conducted around Pb slag contaminated sites in Ibadan, Nigeria to assess the intake of trace metals by cows reared around the contaminated sites as indication of heavy metals contamination. Levels of Pb, Cd, Cu and Zn in blood, milk and faeces were determined in 20 cows exposed to the sites and 20 reference cows from uncontaminated areas. Chemical analysis of pasture grasses and leachate from the contaminated sites showed high levels of Pb. Range and mean levels of Pb, Cd, Cu and Zn in the forage grasses are: 209-899 (425 ± 79.0), ND-1.87 (0.94 ± 0.23), 4.01-8.78 (6.26 ± 0.62) and 17.4-202 (79.2 ± 23.5) mg/kg respectively. The mean values of 8.81±0.06, 0.041±0.003, 0.20±0.01 and 1.00±0.004 mg/L were obtained l for leachate Pb, Cd, Cu and Zn. Difference in blood and milk Pb was highly significant (p<0.01) between the two groups of animals. Mean, median and range blood Pb concentration of 349±82.0, 312,

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